Managing runoff and soil loss in asparagus production systems

Abstract

On slightly sloping land, current asparagus cultivation practices (including prolonged periods of bare soil, surface capping and compaction of wheelings) can lead to runoff and soil loss. This can result in on-site impacts to crops and field operations and offsite impacts on the wider environment. Research into soil and water management in green asparagus production has been undertaken in the UK since 2010. This paper details two separate runoff and erosion trials conducted in 2012 and 2013 on commercial asparagus fields. Each trial has tested the efficacy of a range of treatments applied to inter-row wheelings including green waste compost (of PAS:100 quality protocol standard) and wheat straw mulch at different application rates, both with and without shallow soil disturbance. It was realised early on that compost was ineffective in runoff and soil loss management where application quantity was restricted by nitrogen regulations in Nitrate Vulnerable Zones. Straw mulch alone has consistently reduced soil loss across both trials by 72 to 87% as compared to the bare soil control. Shallow soil disturbance alone reduced soil loss by 4 to 13%, with no significant differences observed between various tillage implements tested. Despite the reductions observed in soil loss, runoff sediment concentration still exceeds that stipulated by EU Directive for surface water quality; risking pollution of any receiving water bodies. The knowledge gained from these studies should be used to develop more effective runoff and soil loss control in order to ensure the future sustainability of asparagus production.